Santiago Arrais

• Master of Science
• National Polytechnic School

The monitoring of the frequency, intensity/magnitude and dynamics of explosive events at volcanoes in a state of unrest is key to surveying and forecasting their activity. Thermal and visual video observations of eruptive phenomena, and their correlation with data from deformation and seismic networks, are often limited by technical constraints inc...

Organizations responsible for seismic and volcanic monitoring worldwide mainly gather information from instrumental networks composed of specialized sensors, data-loggers, and transmission equipment. This information must be available in seismological data centers to improve early warning diffusion. Furthermore, this information is necessary for re...

The new generation of security threats has been promoted by digital currencies and real-time applications, where all users develop new ways to communicate on the Internet. Security has evolved in the need of privacy and anonymity for all users and his portable devices. New technologies in every field prove that users need security features integrat...

A large earthquake (Mw 7.7) occurred on 16 April 2016 within the source region of the 1906 earthquake in the Ecuador-Colombia subduction zone. The 1906 event has been interpreted as a megathrust earthquake (Mw 8.8) that ruptured the source regions of smaller earthquakes in 1942, 1958, and 1979 in this subduction. Our seismic analysis indicated that...

We present continuous SO2 measurements performed at Tungurahua volcano with a permanent network of 4 scanning DOAS instruments between 2007 and 2013. The volcano has been erupting since September 1999, but on the contrary to the first years of eruption when the activity was quasi-continuous, the activity transitioned in late 2008 towards the occurr...

In 1988, the Instituto Geofisico (IG) began a permanent surveillance of Ecuadorian volcanoes, and due to activity on Guagua Pichincha, SP seismic stations and EDM control lines were then installed. Later, with the UNDRO and OAS projects, telemetered seismic monitoring was expanded to Tungurahua, Cotopaxi, Cuicocha, Chimborazo, Antisana, Cayambe, Ce...

We systematically used two approaches to analyze broadband seismic signals for monitoring active volcanoes: one is waveform inversion of very-long-period (VLP) signals assuming possible source mechanisms; the other is a source location method of long-period (LP) events and tremor using their amplitudes. The deterministic approach of the waveform in...

Cotopaxi is an active ice-capped stratovolcano (5898 m a.s.l.) located in the central part of the Northern Volcanic Zone of the Andes, 60 km SE from Quito. Its Holocene magmatism has presented a bi-modal andesitic-rhyolitic character, but only andesitic eruptions have occurred during the last ~2100 years. The last explosive events occurred in 1877...

Ecuador has 55 active volcanoes in the northern half of the Ecuadorian Andes. There, consequences of active volcanism include ashfalls, pyroclastic flows (fast moving fluidized material of hot gas, ash, and rock), and lahars (mudflows), which result in serious damage locally and regionally and thus are of major concern to Ecuadorians. In particular...

Tungurahua and Cotopaxi are andesitic active volcanoes in Ecuadorian Andes. Tungurahua continues its eruptive activity since 1999, in which explosive eruptions accompanying pyroclastic flows occurred in July- August, 2006. Cotopaxi is one of the world's highest glacier-clad active volcanoes, and its seismic activity remains high since 2001. To enha...